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[Qemu-devel] [PATCHv5] block/get_block_status: avoid redundant callouts
From: |
Peter Lieven |
Subject: |
[Qemu-devel] [PATCHv5] block/get_block_status: avoid redundant callouts on raw devices |
Date: |
Mon, 7 Oct 2013 07:59:11 +0200 |
if a raw device like an iscsi target or host device is used
the current implementation makes a second call out to get
the block status of bs->file.
Signed-off-by: Peter Lieven <address@hidden>
---
v5: add a generic get_lba_status function in the raw driver which
adds the BDRV_BLOCK_RAW flag. bdrv_co_get_block_status will
handle the callout to bs->file then.
v4: use a flag to detect the raw driver instead of the strncmp
hack
block.c | 4 ++++
block/raw_bsd.c | 3 ++-
include/block/block.h | 4 ++++
3 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/block.c b/block.c
index 93e113a..38a589e 100644
--- a/block.c
+++ b/block.c
@@ -3147,6 +3147,10 @@ static int64_t coroutine_fn
bdrv_co_get_block_status(BlockDriverState *bs,
return ret;
}
+ if (ret & BDRV_BLOCK_RAW) {
+ return bdrv_get_block_status(bs->file, sector_num, nb_sectors, pnum);
+ }
+
if (!(ret & BDRV_BLOCK_DATA)) {
if (bdrv_has_zero_init(bs)) {
ret |= BDRV_BLOCK_ZERO;
diff --git a/block/raw_bsd.c b/block/raw_bsd.c
index d4ace60..308d605 100644
--- a/block/raw_bsd.c
+++ b/block/raw_bsd.c
@@ -62,7 +62,8 @@ static int64_t coroutine_fn
raw_co_get_block_status(BlockDriverState *bs,
int64_t sector_num,
int nb_sectors, int *pnum)
{
- return bdrv_get_block_status(bs->file, sector_num, nb_sectors, pnum);
+ return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID |
+ (sector_num << BDRV_SECTOR_BITS);
}
static int coroutine_fn raw_co_write_zeroes(BlockDriverState *bs,
diff --git a/include/block/block.h b/include/block/block.h
index f808550..003699e 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -84,6 +84,9 @@ typedef struct BlockDevOps {
/* BDRV_BLOCK_DATA: data is read from bs->file or another file
* BDRV_BLOCK_ZERO: sectors read as zero
* BDRV_BLOCK_OFFSET_VALID: sector stored in bs->file as raw data
+ * BDRV_BLOCK_RAW: used internally to indicate that the request
+ * was answered by the raw driver and that one
+ * should look in bs->file directly.
*
* If BDRV_BLOCK_OFFSET_VALID is set, bits 9-62 represent the offset in
* bs->file where sector data can be read from as raw data.
@@ -105,6 +108,7 @@ typedef struct BlockDevOps {
#define BDRV_BLOCK_DATA 1
#define BDRV_BLOCK_ZERO 2
#define BDRV_BLOCK_OFFSET_VALID 4
+#define BDRV_BLOCK_RAW 8
#define BDRV_BLOCK_OFFSET_MASK BDRV_SECTOR_MASK
typedef enum {
--
1.7.9.5
- [Qemu-devel] [PATCHv5] block/get_block_status: avoid redundant callouts on raw devices,
Peter Lieven <=